ci: Update Ubuntu images from 22.04 to 24.04

Match the main BuildStream repository.
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a38e376..5762246 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -26,7 +26,7 @@
 
 jobs:
   tests:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     continue-on-error: ${{ matrix.allow-failure || false }}
 
     strategy:
@@ -48,6 +48,9 @@
             allow-failure: true
 
     steps:
+      - name: Disable AppArmor restriction for bubblewrap
+        run: sudo sysctl -w kernel.apparmor_restrict_unprivileged_userns=0
+
       - name: Check out repository
         uses: actions/checkout@v2
         # BuildStream requires tags to be able to find its version.
@@ -59,8 +62,11 @@
           ${GITHUB_WORKSPACE}/.github/run-ci.sh ${{ matrix.test-name }}
 
   docs:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     steps:
+      - name: Disable AppArmor restriction for bubblewrap
+        run: sudo sysctl -w kernel.apparmor_restrict_unprivileged_userns=0
+
       - name: Check out repository
         uses: actions/checkout@v2
         # BuildStream requires tags to be able to find its version.
diff --git a/.github/workflows/merge.yml b/.github/workflows/merge.yml
index 67ef1a4..c40ede3 100644
--- a/.github/workflows/merge.yml
+++ b/.github/workflows/merge.yml
@@ -8,8 +8,11 @@
 jobs:
   build:
     name: Build documentation
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     steps:
+    - name: Disable AppArmor restriction for bubblewrap
+      run: sudo sysctl -w kernel.apparmor_restrict_unprivileged_userns=0
+
     - name: Checkout code
       uses: actions/checkout@v2
       # BuildStream requires tags to be able to find its version.
@@ -40,9 +43,12 @@
 
   publish:
     needs: build
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     steps:
 
+    - name: Disable AppArmor restriction for bubblewrap
+      run: sudo sysctl -w kernel.apparmor_restrict_unprivileged_userns=0
+
     - name: Download artifact
       uses: actions/download-artifact@v4
       with: